Patchwork rose_dev: fix memcpy-bug in rose_set_mac_address

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Submitter danborkmann@iogearbox.net
Date March 27, 2012, 1:27 p.m.
Message ID <4F71C05C.4040300@iogearbox.net>
Download mbox | patch
Permalink /patch/148948/
State Rejected
Delegated to: David Miller
Headers show

Comments

danborkmann@iogearbox.net - March 27, 2012, 1:27 p.m.
This patch fixes a small bug in rose_set_mac_address. If the current and new
MAC addresses match, then nothing needs to be done. However memcpy was used
instead of memcmp for comparison.

The patch is against the latest net-tree.

Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>
Cc: Ralf Baechle <ralf@linux-mips.org>
---
 net/rose/rose_dev.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

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David Miller - March 28, 2012, 2:49 a.m.
From: Daniel Borkmann <danborkmann@iogearbox.net>
Date: Tue, 27 Mar 2012 15:27:56 +0200

> This patch fixes a small bug in rose_set_mac_address. If the current and new
> MAC addresses match, then nothing needs to be done. However memcpy was used
> instead of memcmp for comparison.
> 
> The patch is against the latest net-tree.
> 
> Signed-off-by: Daniel Borkmann <daniel.borkmann@tik.ee.ethz.ch>

You're breaking this code, not fixing it.

If you don't keep the memcpy, then the calls right below which setup
the loopback node will use the previous device address not the new
one being configured.
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Patch

diff --git a/net/rose/rose_dev.c b/net/rose/rose_dev.c
index 178ff4f..3c5ce5e 100644
--- a/net/rose/rose_dev.c
+++ b/net/rose/rose_dev.c
@@ -96,7 +96,7 @@  static int rose_set_mac_address(struct net_device *dev, void *addr)
 	struct sockaddr *sa = addr;
 	int err;
 
-	if (!memcpy(dev->dev_addr, sa->sa_data, dev->addr_len))
+	if (!memcmp(dev->dev_addr, sa->sa_data, dev->addr_len))
 		return 0;
 
 	if (dev->flags & IFF_UP) {